public class MainActivity extends FragmentActivity implements OnClickListener {

// 三个tab布局

private RelativeLayout knowLayout, iWantKnowLayout, meLayout;

// 底部标签切换的Fragment

private Fragment knowFragment, iWantKnowFragment, meFragment,

currentFragment;

// 底部标签图片

private ImageView knowImg, iWantKnowImg, meImg;

// 底部标签的文本

private TextView knowTv, iWantKnowTv, meTv;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

initUI();

initTab();

}

/**

* 初始化UI

*/

private void initUI() {

knowLayout = (RelativeLayout) findViewById(R.id.rl_know);

iWantKnowLayout = (RelativeLayout) findViewById(R.id.rl_want_know);

meLayout = (RelativeLayout) findViewById(R.id.rl_me);

knowLayout.setOnClickListener(this);

iWantKnowLayout.setOnClickListener(this);

meLayout.setOnClickListener(this);

knowImg = (ImageView) findViewById(R.id.iv_know);

iWantKnowImg = (ImageView) findViewById(R.id.iv_i_want_know);

meImg = (ImageView) findViewById(R.id.iv_me);

knowTv = (TextView) findViewById(R.id.tv_know);

iWantKnowTv = (TextView) findViewById(R.id.tv_i_want_know);

meTv = (TextView) findViewById(R.id.tv_me);

}

/**

* 初始化底部标签

*/

private void initTab() {

if (knowFragment == null) {

knowFragment = new ZhidaoFragment();

}

if (!knowFragment.isAdded()) {

// 提交事务

getSupportFragmentManager().beginTransaction()

.add(R.id.content_layout, knowFragment).commit();

// 记录当前Fragment

currentFragment = knowFragment;

// 设置图片文本的变化

knowImg.setImageResource(R.drawable.btn_know_pre);

knowTv.setTextColor(getResources()

.getColor(R.color.bottomtab_press));

iWantKnowImg.setImageResource(R.drawable.btn_wantknow_nor);

iWantKnowTv.setTextColor(getResources().getColor(

R.color.bottomtab_normal));

meImg.setImageResource(R.drawable.btn_my_nor);

meTv.setTextColor(getResources().getColor(R.color.bottomtab_normal));

}

}

@Override

public void onClick(View view) {

switch (view.getId()) {

case R.id.rl_know: // 知道

clickTab1Layout();

break;

case R.id.rl_want_know: // 我想知道

clickTab2Layout();

break;

case R.id.rl_me: // 我的

clickTab3Layout();

break;

default:

break;

}

}

/**

* 点击第一个tab

*/

private void clickTab1Layout() {

if (knowFragment == null) {

knowFragment = new ZhidaoFragment();

}

addOrShowFragment(getSupportFragmentManager().beginTransaction(), knowFragment);

// 设置底部tab变化

knowImg.setImageResource(R.drawable.btn_know_pre);

knowTv.setTextColor(getResources().getColor(R.color.bottomtab_press));

iWantKnowImg.setImageResource(R.drawable.btn_wantknow_nor);

iWantKnowTv.setTextColor(getResources().getColor(

R.color.bottomtab_normal));

meImg.setImageResource(R.drawable.btn_my_nor);

meTv.setTextColor(getResources().getColor(R.color.bottomtab_normal));

}

/**

* 点击第二个tab

*/

private void clickTab2Layout() {

if (iWantKnowFragment == null) {

iWantKnowFragment = new IWantKnowFragment();

}

addOrShowFragment(getSupportFragmentManager().beginTransaction(), iWantKnowFragment);

knowImg.setImageResource(R.drawable.btn_know_nor);

knowTv.setTextColor(getResources().getColor(R.color.bottomtab_normal));

iWantKnowImg.setImageResource(R.drawable.btn_wantknow_pre);

iWantKnowTv.setTextColor(getResources().getColor(

R.color.bottomtab_press));

meImg.setImageResource(R.drawable.btn_my_nor);

meTv.setTextColor(getResources().getColor(R.color.bottomtab_normal));

}

/**

* 点击第三个tab

*/

private void clickTab3Layout() {

if (meFragment == null) {

meFragment = new MeFragment();

}

addOrShowFragment(getSupportFragmentManager().beginTransaction(), meFragment);

knowImg.setImageResource(R.drawable.btn_know_nor);

knowTv.setTextColor(getResources().getColor(R.color.bottomtab_normal));

iWantKnowImg.setImageResource(R.drawable.btn_wantknow_nor);

iWantKnowTv.setTextColor(getResources().getColor(

R.color.bottomtab_normal));

meImg.setImageResource(R.drawable.btn_my_pre);

meTv.setTextColor(getResources().getColor(R.color.bottomtab_press));

}

/**

* 添加或者显示碎片

*

* @param transaction

* @param fragment

*/

private void addOrShowFragment(FragmentTransaction transaction,

Fragment fragment) {

if (currentFragment == fragment)

return;

if (!fragment.isAdded()) { // 如果当前fragment未被添加，则添加到Fragment管理器中

transaction.hide(currentFragment)

.add(R.id.content_layout, fragment).commit();

} else {

transaction.hide(currentFragment).show(fragment).commit();

}

currentFragment = fragment;

}

}